If your ABS is working, it can only be the parts of the system that don't have anything to do with the ABS. For this reason it CAN'T be a wheel speed sensor.
Your possible culprits are:
The high pressure pump mounted to the PMV (cannot be changed without the entire PMV 320 bucks)
The traction portion of the EBCM (700 bucks)
This being the case, if you want it working, it'* worth your time to have the dealer scan it for $100. Both items are fairly easy to change.
I personally prefer the traction to be working, but I have a different system than the newer cars. Mine doesn't do anything in hard cornering. Just helps me off the line when things are wet. I'd still like to see some 0-60 times with and without the traction. I'm planning to get both of my systems fixed before the end of the year, but to do it, I'm changing both rear hub assemblies and the PMV. My EBCM is ok, thank god.